Avoided cleanup at startup + added mutex for lastCleanupTime

datastore/datastore/storagebackend/postgresql/init.go

@@ -10,13 +10,15 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 )
 
 // package variables (only accessible within postgresql package)
 var (
 	cleanupInterval time.Duration // minimum time period between calls to cleanup()
 	lastCleanupTime time.Time     // time of last call to cleanup()
+	lctMutex        sync.Mutex    // mutex to protect access to lastCleanupTime
 
 	putObsLimit int // max # of observations in a single call to PutObservations
 
@@ -129,7 +131,7 @@ func initPutObsLimit() {
 func init() { // automatically called once on program startup (on first import of this package)
 
 	initCleanupInterval()
-	lastCleanupTime = time.Time{}
+	lastCleanupTime = time.Now() // avoid immediate cleanup on startup
 
 	initPutObsLimit()
 

datastore/datastore/storagebackend/postgresql/postgresql.go

@@ -546,7 +546,13 @@ func cleanup(db *sql.DB) error {
 
 // considerCleanup considers if cleanup() should be called.
 func considerCleanup(db *sql.DB) error {
+
 	// call cleanup() if at least cleanupInterval has passed since the last time it was called
+
+	// ensure atomic access to lastCleanupTime
+	lctMutex.Lock()
+	defer lctMutex.Unlock()
+
 	if time.Since(lastCleanupTime) > cleanupInterval {
 		if err := cleanup(db); err != nil {
 			return fmt.Errorf("cleanup() failed: %v", err)